The customary synthesis of cyanoacetic esters is carried out by cyanidation of sodium chloroacetate in aqueous solution, followed by an acid-catalyzed esterification with the appropriate alcohol, where the water formed is distilled off azeotropically. An essential disadvantage of this two-step process is the fact that the water has to be removed after cyanidation, since the subsequent esterification is only possible under substantially water-free conditions. On an industrial scale, that is usually carried out by evaporating the water.
Since the sodium cyanoacetate, which is formed as an intermediate, is moreover highly water-soluble, a method for its esterification in water as the solvent is desirable.